Key Takeaways
- Net billing credits exports below the retail rate — typically at wholesale or avoided-cost values
- Creates a “spread” between import cost and export credit that incentivizes self-consumption
- Increasingly replacing 1:1 net metering as states restructure solar compensation
- Makes battery storage economically attractive by increasing the value of stored solar energy
- Requires more sophisticated financial modeling than traditional net metering
- California’s NEM 3.0 is the most prominent example of a net billing framework
What Is Net Billing?
Net billing is a solar compensation structure where electricity exported to the grid is credited at a rate lower than the retail electricity price. Unlike traditional net metering (where each exported kWh offsets one imported kWh at full retail value), net billing values exports at a separate — usually lower — rate, often based on wholesale electricity prices, avoided cost calculations, or a fixed feed-in rate.
The distinction matters: under 1:1 net metering, the grid functions as a free battery because every kWh you send out comes back at full value. Under net billing, the grid is more like a bank that charges a transaction fee — you deposit energy at one rate and withdraw at a higher rate.
Net billing fundamentally changes how solar systems should be designed. With solar design software that models both import and export rates separately, designers can optimize for self-consumption rather than maximum production — a critical distinction for customer economics.
How Net Billing Works
Net billing introduces a two-rate system that applies simultaneously:
Solar Generation
The solar system generates electricity. Any power consumed on-site displaces grid imports at the full retail rate — this part works the same as net metering.
Excess Power Exported
When generation exceeds on-site consumption, surplus electricity flows to the grid. Under net billing, this export is metered separately from imports.
Export Credited at Reduced Rate
Exported kWh receive credits at the applicable export rate — wholesale, avoided cost, or a fixed tariff. This rate is typically 25–75% lower than the retail import rate.
Grid Imports at Full Retail
Electricity consumed from the grid (evenings, cloudy periods) is billed at the full retail TOU rate. The difference between the import rate and export credit creates the economic incentive to maximize self-consumption.
Monthly or Annual Settlement
The utility calculates the net bill by subtracting total export credits from total import charges. The customer pays the difference, plus any fixed charges and non-bypassable fees.
Bill = (Imported kWh × Retail Rate) − (Exported kWh × Export Rate) + Fixed ChargesNet Billing vs. Net Metering
Understanding the difference between these two compensation models is fundamental to solar system design and financial modeling.
1:1 Net Metering
Every exported kWh offsets one imported kWh at the full retail rate. Effectively treats the grid as free storage. Simplest financial model — all kWh have equal value regardless of when they’re produced. Solar-only systems achieve strong ROI.
Net Billing
Exports and imports are valued at different rates. Self-consumed solar is worth the full retail rate; exported solar is worth less. Requires TOU-aware design and often justifies battery storage. More complex but reflects actual grid economics more accurately.
Reduced-Rate Net Metering
A middle ground where exports receive credits at a percentage of the retail rate (e.g., 75% or 80%). Simpler than full net billing but still creates an incentive for self-consumption. Used in several U.S. states.
Feed-in Tariff
All solar production (not just exports) is compensated at a fixed contractual rate for 10–25 years. Common in European markets. Provides revenue certainty but may be above or below market rates depending on when the contract was signed.
In net billing markets, a system that produces 10,000 kWh with 80% self-consumption generates more financial value than a system producing 12,000 kWh with 50% self-consumption. Solar software must optimize for financial returns, not just total energy production.
Key Metrics & Calculations
Net billing economics depend on the spread between import and export rates:
| Metric | Typical Net Metering | Typical Net Billing | Difference |
|---|---|---|---|
| Export Credit Rate | $0.25–$0.45/kWh (retail) | $0.04–$0.12/kWh (wholesale) | 60–85% lower |
| Import Rate | $0.25–$0.45/kWh | $0.25–$0.45/kWh | Same |
| Rate Spread | $0/kWh | $0.15–$0.35/kWh | Drives self-consumption value |
| Self-Consumed kWh Value | $0.25–$0.45 (same) | $0.25–$0.45 (same) | Same |
| Exported kWh Value | $0.25–$0.45 (same) | $0.04–$0.12 | Much lower |
| Optimal Self-Consumption | 30–40% (acceptable) | 70–85% (target) | Battery needed |
Battery Value per Cycle = Shifted kWh × (Import Rate − Export Rate) × (1 − Round-Trip Loss)Practical Guidance
Net billing markets require different strategies from every solar professional:
- Prioritize self-consumption in system sizing. Oversizing creates diminishing returns under net billing because excess exports are worth far less than displaced imports. Size to match the customer’s daytime load profile.
- Include battery storage in every proposal. The rate spread between import and export creates a clear economic case for batteries. A battery that shifts 10 kWh from midday export ($0.06/kWh) to evening self-consumption ($0.40/kWh) saves $3.40/day.
- Model hourly intervals, not monthly averages. Net billing economics vary by hour. Solar design software with hourly production and consumption modeling produces far more accurate savings projections than monthly or annual averages.
- Evaluate west-facing panels for TOU alignment. If peak import rates coincide with late afternoon, west-facing panels that produce during those hours may generate more financial value than south-facing panels with higher total kWh.
- Plan for battery installations on most jobs. Net billing markets make batteries the standard, not the exception. Ensure crews are trained on battery installation, electrical integration, and commissioning.
- Install hybrid inverters even on solar-only projects. Customers in net billing markets often add batteries within 1–3 years. A hybrid inverter avoids a costly retrofit later.
- Configure battery dispatch for TOU optimization. Set the battery to charge from solar during low-value export hours and discharge during high-value peak import hours. Default settings may not be optimized for the customer’s specific rate schedule.
- Set up monitoring with export tracking. Customers in net billing markets need to see their export volumes and self-consumption ratios to understand their system’s performance and value.
- Reframe the value proposition. Under net billing, the pitch shifts from “sell your excess power” to “use your own power and stop buying expensive grid electricity.” Self-consumption is the primary value driver.
- Lead with solar-plus-storage proposals. Solar-only proposals in net billing markets show longer payback periods that can deter customers. Solar-plus-storage proposals restore competitive payback economics.
- Show the rate escalation advantage. Even with lower export credits, solar locks in a significant portion of the customer’s energy cost. As retail rates rise 3–5% annually, the savings grow each year.
- Emphasize backup power. Since batteries are already justified economically under net billing, backup power during outages becomes an included benefit rather than an additional expense. This resonates with customers.
Optimize Solar + Storage for Net Billing
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Real-World Examples
Residential: Net Billing Without Battery
A homeowner in California installed a 7 kW system under NEM 3.0 net billing. The system produces 10,500 kWh/year. With a daytime-heavy work schedule, only 35% is self-consumed; the remaining 65% is exported at an average ACC rate of $0.06/kWh. Year-one savings total $1,050 with a 13+ year payback — highlighting the penalty of low self-consumption under net billing.
Residential: Net Billing With Battery
The same homeowner adds a 13.5 kWh battery. Self-consumption rises to 82% as the battery stores midday overproduction for evening use. Year-one savings increase to $2,350, cutting the payback period to under 7 years for the combined solar-plus-storage system. The battery earns its cost back in 4 years through the import/export rate arbitrage.
Commercial: Demand Charge Reduction
A manufacturing facility in Arizona under a net billing tariff installed 200 kW solar with 400 kWh battery storage. The battery not only shifts solar for self-consumption but also reduces monthly demand charges by $1,200/month through peak shaving. Combined energy and demand savings yield a 4.5-year payback period.
Impact on System Design
Net billing changes fundamental design assumptions compared to net metering:
| Design Decision | Net Metering (1:1) | Net Billing |
|---|---|---|
| System Size Goal | 100–120% of annual usage | 80–100% of daytime load |
| Battery Storage | Optional (grid is free battery) | Standard (essential for ROI) |
| Panel Orientation | South (max total kWh) | South/West (max value timing) |
| Financial Model Complexity | Simple — one rate | Complex — import + export rates + TOU |
| Self-Consumption Target | 30–40% acceptable | 70–85% target |
| Payback (Solar Only) | 5–7 years | 9–12+ years |
| Payback (Solar + Battery) | N/A | 6–9 years |
In net billing markets, request the customer’s 15-minute or hourly interval usage data from the utility (Green Button data in California). This level of detail reveals the actual self-consumption potential and battery sizing requirements — monthly usage totals are not sufficient for accurate net billing modeling.
Frequently Asked Questions
What is the difference between net metering and net billing?
Under net metering, exported solar electricity is credited at the same retail rate you pay for imports — each exported kWh offsets one imported kWh at full value. Under net billing, exports are credited at a lower rate (typically the wholesale or avoided-cost rate), which is often 60–85% less than the retail rate. This rate difference makes self-consumption and battery storage much more important under net billing.
Is net billing replacing net metering?
In many markets, yes. California replaced its net metering program with net billing (NEM 3.0) in 2023. Several other states are considering or implementing similar transitions. The trend reflects regulators’ view that full retail-rate credits overcompensate solar owners at the expense of non-solar ratepayers. However, many states still offer traditional net metering, and the transition timelines vary widely.
Do I need a battery with net billing?
A battery is not required, but it is strongly recommended under net billing. Without a battery, you export solar during the day at low rates and import from the grid at high rates in the evening. A battery stores your midday solar and uses it during expensive peak hours, effectively capturing the full retail value of that energy instead of the reduced export credit. In most net billing markets, adding a battery cuts the payback period by 3–5 years.
Which states use net billing instead of net metering?
As of 2026, California is the most prominent state using net billing (NEM 3.0). Hawaii, Arkansas, Louisiana, and parts of several other states have also moved to net billing or reduced-rate net metering. The policies are evolving rapidly — states like North Carolina, Florida, and Indiana have active proceedings that may shift their compensation structures. Check the Database of State Incentives for Renewables and Efficiency (DSIRE) for current state-by-state policies.
About the Contributors
CEO & Co-Founder · SurgePV
Keyur Rakholiya is CEO & Co-Founder of SurgePV and Founder of Heaven Green Energy Limited, where he has delivered over 1 GW of solar projects across commercial, utility, and rooftop sectors in India. With 10+ years in the solar industry, he has managed 800+ project deliveries, evaluated 20+ solar design platforms firsthand, and led engineering teams of 50+ people.
Content Head · SurgePV
Rainer Neumann is Content Head at SurgePV and a solar PV engineer with 10+ years of experience designing commercial and utility-scale systems across Europe and MENA. He has delivered 500+ installations, tested 15+ solar design software platforms firsthand, and specialises in shading analysis, string sizing, and international electrical code compliance.